Key-frame for pianos.



J. P. GAULFIELD. KEY FRAME FOR PIANOS.

APPLICATION FILED 00;. 17, 1908.

Patented Mar. 22, 1910.

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UNITED STATES PATENT OFFICE.

JAMES P. CAULFIELD, OF BALTIIVIORE, lVIAR'YLAND.

KEY-FRAME FOR PIANOS.

to provide a frame of improved construcction that will be free of allliability to warp or twist; that will require less space or room andwhich may be readily adjusted with respect. to the action and the keybottom.

The invention is illustrated in the accompanying drawing, in which,

Figure 1, shows a plan view of the key frame resting upon the key bottomand also shows .some of the keys mounted thereon.

2 Fig. 2, shows a front elevation of the same.

Fi 3 is a cross-sectional view throu h the key bottom and key frame,thesection being taken on the line 3 3 of Fig. 1, and

Fig. =1, is a cross-section on an enlarged scale through the key-frameand illustrates the adjusting screws.

In the drawing the numeral, 1, designates the wood key bottom of thepiano with the key blocks, 2, at opposite ends thereof and 0 on whichbottom the key frame is supported.

The key frame comprises a plurality of flat metal strips, 3, which restflat upon the top surface of the key bottom. In the present instancefour of these metal strips are 5 employed but obviously the number mayvary. At their rear ends the strips, 3, support a metal rail, 5, whichext-ends from one end of the key frame to the other, as clearly seen inFig. 1, and screws, 41:, extend through the said rail and also throughthe strip to secure the two down on the key bottom. Between the ends,the flat strips support an elevated horizontal metal balance rail, 6,and said rail is supported so as to be adjusted with respect to saidstrips so that it may be raised or lowered above the same. In thepresent instance the devices employed to effect this adjustment comprisea central screw, 7, which passes freely through the rail and the lowerend of which screws into a threaded opening similar to the opening, 8,shown in Fig. 4 while at opposite sides of said screw the rail isprovided with set screws, 9, which screw through said bar and whoselower ends merely contact with the Specification of Letters Patent.

Application filed October 17, 1908.

Patented Mar. 22, 1910. Serial No. 458,162.

upper surface of the strip, 3. It will thus be seen that by turning thecentral screws so as to elevate them and then turning the setscrews soas to move them down through the rail that the latter will thereby beelevated with respect to the fiat metal strips and thus effect avertical movement of the rail with respect to the key bottom and thestrips thereon. By reference to Fig. 3 it will be seen that the uppersurface of the rail, 6, has a beveled front edge, 10, and that be tweenthe opposite longitudinal edges said rail is provided with verticalpins, 11, for a purpose presently to be described. At the front ends,the flat metal stri as are further provided with central screws, andside setscrews, S), for only supporting a front metal rail, 12. Thismetal rail is also provided with upwardlyprojecting pins, 13, andsuitable cushions in the present instance having the form of washers, 11, are placed over the pins so as to rest upon the upper side of thefront rail, 12, as shown in Figs. 2 and 3. The keys, 15, are providedwith the usual slots, 16, midway between their ends and through whichthe pins, 11, project so as to pivotally sustain the keys on the centerrail, (3, of the metal key frame.

It is obvious that the rails, G, and 12, of the key frame may be raisedor lowered i11- dependently of each other so as to adjust them properlywith respect to the key bottom and that when adjusted the parts allbeing of metal will not be affected by variations in the temperature orby dampness and that if at any time adjustment of the rails is desirablethe same can be made readily and Without removal of all the keys and keyframe.

By means of the construction described the space above the key-bottomordinarily required for the frames may be much reduced.

Having thus described my invention what I claim and desire to secure byLetters Patent is,

1. A key-frame for pianos comprising a plurality of metal strips havingscrewthreaded openings between their ends, a central metal balance railextending crosswise of and above the strips and having smooth openingsand threaded openings therein, screws extending through the smoothopenings of the balance rail and entering the threaded openings in thestrips beneath and screws passing through the threaded openings of therail and engaging the strips to effect an adjustment of the bar.

2. A key-frame for pianos comprising a plurality of metal strips eachhaving a screw-threaded openings; a front rail 0&- tending crosswise ofthe strip ends and having threaded and smooth openings adjacent eachother; adjusting screws passing through the threaded openings of therail and sustaining the latter in an elevated position; screws passingthrough the smooth openings of the rail and entering the threadedopenings of the strips beneath a central balance rail also extendingcrosswise of the strips, and means for adjustably sustaining saidbalance rail.

In testimony whereof I affix my signature in presence of two witnesses.

JAMES P. CAULFIELI). Vitnesses LOUIS J. Ro'rii, Hownnn Him) I To 1 I.

